Tears bathe the eye, washing out dust and debris and keeping the eye moist. They also contain enzymes that neutralize the microorganisms that colonize the eye. Tears are essential for good eye health.
In dry eye syndrome, the eye doesn't produce enough tears, or the tears have a chemical composition that causes them to evaporate too quickly.
Dry eye syndrome has several causes. It occurs as a part of the natural aging process, especially during menopause, as a side effect of many medications, such as antihistamines, antidepressants, certain blood pressure medicines, Parkinson's medications, and birth control pills; or dry, dusty or windy climates. Home or office air conditioning or a dry heating system can also dry out eyes. Another cause is insufficient blinking, such as when a person stares at a computer screen all day.
Dry eyes are also a symptom of systemic diseases such as lupus, rheumatoid arthritis, rosacea or Sjogren's syndrome (a triad of dry eyes, dry mouth, and rheumatoid arthritis or lupus).
Long-term contact lens wear is another cause; in fact, dry eyes are the most common complaint among contact lens wearers. Recent research indicates that contact lens wear and dry eyes can be a vicious cycle. Dry eye syndrome makes contact lenses feel uncomfortable, and the rubbing of the lenses against the conjunctiva seems to be a cause of dry eyes.
Incomplete closure of the eyelids, eyelid disease and a deficiency of the tear-producing glands are other causes. Tears are composed of three layers: the outer, oily, lipid layer; the middle, watery, lacrimal layer; and the inner, mucous or mucin layer. Each layer is produced by a different part of the eye (the lacrimal gland produces the lacrimal layer, for example), so a problem with any of those sources can result in dry eyes.
Dry eye syndrome is more common in women, possibly due to hormone fluctuations. Recent research suggests that smoking, too, can increase the risk of dry eye syndrome. With increased popularity of eyelid surgery for improved appearance, dry eye complaints now occasionally are associated with incomplete closure of eyelids following a procedure.
Dry eye syndrome is an ongoing condition that may not be cured (depends on the cause), but the accompanying dryness, scratchiness and burning can be managed. Artificial tears can be used, which are lubricating eyedrops that may alleviate the dry, scratching feeling.
Restasis eyedrops (cyclosporine in a castor oil base) go one step further: they help the eyes to increase tear production.
Sometimes people use the eye drops that “get the red out” to treat their dry eyes. This won't work unless the eye drops also contain artificial tears, and the original “get-the-red-out” formulation doesn't. These drops can reduce or eliminate the redness temporarily, but they don't treat the cause of the redness, whether it's dryness, environmental irritation, or some other problem.
Not only that, but the vasoconstrictors in those formulas that reduce redness by contracting the eye's blood vessels are addictive, in the sense that over time, more and more is needed to achieve the same effect. And with frequent use, the effect diminishes after a while, anyway—the blood vessels simply won't constrict as much as they did when you first used the drops.
Thus there is a clear and present need for new and improved devices and methods for the treatment of dry eye syndrome.